The Pakistan team poses with the winners' trophy after the 3rd T20I.
No nation was willing to tour Pakistan since the 2009 terrorist attack on the Sri Lankan team bus, which killed eight people and injured seven Sri Lankan players. It could be the first time that a three-match global series will be played without a single rest day in between.
"I have been working day and night to conclude an agreement with West Indies which I have finalized", PCB chairperson Najam Sethi said.
West Indies are the reigning World Twenty20 champions after winning the title in India in 2016.
West Indies are set to become the latest global team to tour Pakistan.
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The matches, which were initially scheduled to be played in Lahore, will now be carried out in Karachi.
"This is how we intend to bring Karachi back on map of cricket", he added. The PSL final, and now three more games for Karachi as per routine.
"Good news! West Indies have agreed to play three T20 matches in Karachi on 1st, 2nd and 4th April", wrote the PCB chief on Twitter, adding: "CM Sindh is fully supporting this PCB initiative".
An ICC security consultant will visit Karachi during the PSL final and Sethi said the PCB has contracted the same consultant for the West Indies series.
The National Stadium has undergone renovation and will be ready for the final soon, said Sethi.